Rolling sheet metal



Jan. 24, 1933. J. B. TYTUS ROLLING SHEET METAL Filed 001;. 20, 1927 INVENTOR. T M

A TTORNEYf Patented Jan. 24, 1933 UNITED STATES PATENT OFFICE.

JOHN B. TYTU S, OF MIDDLETOW'N, OHIO, ASSIGNOB TO THE AMERICAN ROLLING MILL COMPANY, OF IIIDDLETO'WN, 01110, A CORPORATION OF OHIO nortme'snnn'r marlin Application filed October so, 1921. Serial no. 227,600.

My invention relates to a process for rolling sheet metal in which sheets of a wide variety of gauges are produced using the Welsh system of rolling" or tin mill rolling practice in the finishing, but in which the packs are formed from thin plate produced in a continuous manner.

' In my application for Letters Patent Serial No. 21,661, filed April 8, 1925, I explain a process wherein using the principle of the rolling of metal with conyexity developed in the piece, which convexity is reduced in each pass, thin plates are formed, which are se: lected for convexity, matched, "heated and rolled into thin sheets.

My present process contemplates a variation over the application for patent alcove referred to, which is based on refining the operation to the end oi assuring packs for the final rolling which are 02% a type which can be made definite in contour, thus resdering the rolling operation" simple.

in the drawing Figures 1 and 2' are diagrams of a plant for the production of sheet metal according to my invention, in plan and elevation.

in the particular design shown, the roll stands 3., 2, 3 and i are formed four high, and the rolls between which the piece passes will he oi relatively small diameter, with large diameter backing rolls, which large diameter rolls are held in roller bearings, and the small diameter rolls driven by a suitable series of motors. This mill of four stands is adapted to receive a hot thiclr slab, and reduce it without cross cutting to along, wide, thin strip, which is of a width that can be sufficient to satisfy sheet mill requirements.

At 5 l have indicated a set or four high cold rolls, the mill of a single stand being similar in nature to the stands in the hot mill. There may be several stands of these cold rolls if required.

As has been developed by me, the system 0;? roll control in efiecting by a continuous roll reduction the attenuation of wide pieces of metal to thin plate er sheet gauges, must be such that the first pass or" a series of passes which acts upon the metal pust before it has reached a thinness that will inhibit lateral flow of metal in the pass, will give a convem'ty to the piece; This convexity then must be reduced proportionately or substantifilly so, in each successive pass.

'In the four high mill selected for illustration, this convexity principle must be followed, and the final piece must have a convexity (crosswise thereof).

It is not highly practical in a rapid reduction process in hot mill rolling of a piece of a single thickness to fairly thin'crosssection, to deliver a strip which is fully satisfactory for pack forming material. There are no rolls available which will long withstand the excessive wear resulting from rapid reduction processes. The result is that the piece develops roughness, the rolls cut out in the active portions and do not give a piece which is accurate as to gauge and a complete control or the contour or" the piece is not always obtained.

in order to obtain plate or sheet bodies which are of a uniform smooth surface and accurate as to gauge, i provide for the cold rolling treatment. in the particular instance, or the series of short strips in the instance illustrated in. my patent application hereinabove referred to,

are delivered from the hotmill they are permitted to cool, and are then given a pass or passes between the cold rolls.

The attentihn to contour in the cold rolls should not be relaxed, and a definite control or the original shape of the rolls, and the composition thereof, and the screw applied thereto, will have to be watched carefully, as well as the sh ape and composition of the piece being cold rolled, to the end of forming an active pass between the rolls of the cold mill which will give a contour to the piece which has been predetermined, as well as an accurate gauge.

The resulting cold rolled product which will be smooth and accurate may then be cut into shorter lengths, and heated up to hot rolling temperature again, and packs formed of the pieces. a l heating point is indicated by the diagram of furnaces at 6.

The severing to length can be after heating, or the matching into packs done before Thus, as the long strip,

heating, and the heating can he done singly in a continuous furnace.

The mills 7, 8 and 9 as shown are intended to indicate several stands of rolls which will he oneratd as individual finishing roll stands, and not in a continuous manner. A set of mills will be required to handle the product of the hot and cold mill. The usual tin mill practice of rolling in pairs, doubling, reheating and re-rolling will he followed in the use of these mills. The packs will he formed of lengthwise sections of the cold rolled pieces so that convexity will he increased in the pack over the convexity of-the parts making up the pack.

Instead of this a continuous sheet mill, similar in general design to the mills l, 2, 3 and 4, could he used.

With the usual system of rolling in the tin mill, sheet hers are provided which are very much thicker and very much shorter than the pieces used in forming my packs. 'lhese bars are first rolled in a pair, on a roughing mill, and the resultant rough plate is heated, rolled in a pack of two on the sheet mill, reheated, doubled, rolled again, etc., in any of the modes adapted from the Welsh "process of rolling. in my system the packs, when they reach the individual rolling stages "for finishing, are already longer than a rough plate pack, and this cuts down the time and the various "problems involved in the usual tin mill practice.

Unless the packs, in this instance, were very accurate in gauge, as Well as heing quite smooth in surface and of known contour,

which contour would he communicated to the roller who handled the packs, it would be impractical, if notiinpossihle, for the packs to be rolled without becoming so Welded toy'practical to adapt one set of sheet rolls to a succession of packs which vary in their contour, orior that matter in their gauge, which ailects theactive pass and hence the contour, hut with a steady supply of packs of a known temperature, the elements of which are smooth and of a lmown contour and. gauge, the individual stand roller can readily handle the material.

It will he desirable to refrain from pick ling the hot rolled material before the cold rolling step indicated so as to leave the hot mill scale. This scale is relied upon by the pack roller to set his pack, and furthermore, will permit o'f openi'ng the packs particularly whenthe gauge is thin.

A pack is said to be set "when, after a pass through the mill, the adjoining component parts adhere to each other over their entire surfaces, hut not so strongly as to prevent the opening up of the pack after the rolling Without damage to the sheets. A loose pack is a pack in which, after a pass through the mill, there is no adhesion of the parts. Both loose ther as to he impossible to strip. it is not packs and set pael'rs are successfully rolled under difierent conditions. An intermediate condition is foundinpatched' packs inwhich the adherence of adjoining parts is irregular and incomplete over their areas. The effect 0:" patches is unequal elongation of the component parts in the patched area. Such un-\ equal elongation causes the welding oi component parts, transverse folding called jumping, or longitudinal ioldin called pinching, any one of which ruins t e pack.

It will he clear that gauge and contour i easier to centre, tne gauge and contour in the slower operating tandem mill, with intermediate shearing, as in my former processes. The intermediate cold rolling sten is, however, quite valuable in the second case, as as in the first, as has heen stated.

in either instance finishing roller need not depart from his regular practice in sheet or tin rolling in which he rolls the pack repeatedly through the individual mills, except to omit the stem of reducing the pair oi sheet cars and giving a :ereliruinar reduction to the pack formed of theloair. i e indeed he given a simpler problem, hecause the very hest type of pack will he iurnished to him ior every operation, and he should he ahle to dispense with one of the final passes hecause of heing able to control his to vantage.

'l-laving thus described my Invention, 1 claim as new and desire to secure by Patent, is 2- 7 l. jlhat rocess of rolling sheet mes which consists in continuously prcducin single thickness nlate or sheet metal by rolling the same when hot, letting the piece cool, giving the piece a cold rolling, in which (leill'lliiB gauge and good surface oi the cold rolled piece is assured, the contour or" the cold rolled piece losing one in which there is a convexity of cross section of the cold rolled piece, and then heating and forming packs of the product, and finally reducing the hot packs to finished gauge lay the use ofa single stand of rolls which repeatedly acts on each such. v

2.. That process oi "rolling sheet metal, which consists in continuously nroducins: single thickness thin plate or sheet metal rolling the same when hot, said niece heing reduced from the slab without cross cutting, as in strip rolling, letting the piece cool, giving the piece a cold rolling, in which definite gauge and good rurziace of theeold rolled piece'is assured, the contbur of the cold rolled piece being one in which there is a convexity of cross section of the cold rolled piece, and then heating and forming packs of the prod- 5 not, and finally reducing the hot packs to finished gauge.

JOHN B. TYTUS. 

